package com.oa.kq.util;

/**
 * 计算两个经纬度之间的距离
 * @author admin
 *
 */
public class LngLatUtils {
	// private static double EARTH_RADIUS = 6378.137;
	private static double EARTH_RADIUS = 6371.393;

	private static double rad(double d) {
		return d * Math.PI / 180.0;
	}

	/**
	 * 计算两个经纬度之间的距离
	 * 
	 * @param lat1
	 * @param lng1
	 * @param lat2
	 * @param lng2
	 * @return
	 */
	public static double getDistance(double lat1, double lng1, double lat2, double lng2) {
		double radLat1 = rad(lat1);
		double radLat2 = rad(lat2);
		double a = radLat1 - radLat2;
		double b = rad(lng1) - rad(lng2);
		double s = 2 * Math.asin(Math.sqrt(
				Math.pow(Math.sin(a / 2), 2) + Math.cos(radLat1) * Math.cos(radLat2) * Math.pow(Math.sin(b / 2), 2)));
		s = s * EARTH_RADIUS;
		s = Math.round(s * 1000);
		return s;
	}

}